Memory devices such as dynamic random access memories (DRAM) are widely used in computing devices, including mobile devices, to store data. To maintain data integrity, DRAMS cells are periodically refreshed. As density and speed of the DRAMs increase, the impact of the refresh operations on DRAM's overall performance and power consumption become more and more non-trivial. The refresh operation impact can be particularly significant in mobile devices since power consumption is of greater concern in such devices.